1. Field of the Invention
The present invention relates to a piezoelectric element of laminate type comprising a plurality of sheet members made of piezoelectric material laminated one on another, which expands or contracts in response to an applied voltage.
2. Discussion of Background
Piezoelectric elements of laminate type have a feature that they are capable of generating a large force although the deformation is small. Therefore, they are expected to be applied as various actuators.
However, in order to operate them with a low voltage, it is necessary to reduce the thickness of each sheet of piezoelectric material constituting the laminate. Many proposals have been made to take out every second electrode. One of them is a method in which an insulating layer is coated on the exposed portion of every second internal electrode by a printing method, and a connecting electrode is then coated over the entire side surface of the element for electrical connection. However, it has been difficult by such a method to constantly form fine patterns. Then, it has been proposed to form such an insulating layer by electrophoresis. However, to carry out this method, it is necessary to provide an external electrode for electrophoresis and to cut and remove this external electrode after the formation of the insulating layer, and thus the process is cumbersome.